Distillation of alcohol from hydrolyzed mixtures of alkyl sulfates and sulfuric acid



Patented July 27, 1948 DISTILLATION OF ALCOHOL FROM HYDRO- LYZED MIXTURES OF ALKYL SULFATES AND SULFURIC ACID Henry 0. Mottern, Hillside, and Francis M. Archibald, Elizabeth, N. J assignors, by niesne assignments, to Standard Oil Development Company, acorporation of Delaware Application November 10, 1944, Serial No. 562,880

3 Claims. (01. soc-51) The present invention relates to the produc- Q tion of alcohols from olefins occurring in cracked petroleum material.

In the manufacture of alcohols from various olefinic materials, the oleflns are absorbed .in sulfuric acid to form the alkyl esters which remain in the acid as an acid extract. The extract is diluted with water to hydrolyze the esters to the corresponding alcohols which are recovered by distillation from the extract. During the absorption of the olefins in the sulfuric acid, particularly when the acid has a concentration of 83% or more, a portion of the oleflns oxidize and polymerize to form higher molecular weight materials which. upon dilution with water separate out as tarry material consisting of oily polymers of solid compounds such as resin acids. Under more extreme conditions these impurities are oxidized to a fiocculent carbon. These tars,

resins and carbon particles cause considerable difficulties in recovering the alcohol from the ilfuric acid extracts. When the acid remaining from the distillation of alcohols is reconcentrated and reused to absorb further amounts of oleflns, the tendency of the tars and resins to carbonize and form flocculent carbon upon dilulution is greatly increased. The carbon, on reabsorption of the olefins in the restored acid, becomes mixed with the tars and resins during the alcohol recovery step and causes much delay and expense in the recovery of the alcohol by collecting in the still in suihcient quantity to require shutdown in order to clean out the distillation equipment. Cleaning of the stills is tedious and time-consuming and in some cases requires the use of expensive solvents to break up the tarry and resinous mass.

It is therefore one object of the invention to prevent the deposit of such tarry and carbonaceous materials in the still during the distillation of the alcohol from the extract. i

It is a further object of this invention to provide a process for the production of alcoholsfrom acid extracts in a continuous manner without any periodic shutdown to clean out the still.

Other objects and a fuller understanding of this invention may be had by referring to the following description and claims taken in conjunction with the accompanying drawing which is a diagrammatic view of the general flow plan .of the process.

According to the present invention, the above objects are accomplished by adding small amounts of sulfonates or sulfonated compounds to the acid extracts fed to the distillation equipment either before or after dilution and hydrolysis with water. The addition of such sulfonated compounds in smaller quantities causes dispersion of the tars, resins, carbon particles, etc., into fine particles which do not coagulate on the wetted surfaces within the still. Thus the recovery of the alcohol by distillation can be continued indefinitely by the use of such sulfonated materials. sulfonated material or 'sulfonates may be added either to the strong acid extracts prior to dilution for hydrolysis or to the diluted extract or to the diluted and hydrolyzed extract prior to counter-current steam distillation. The point of addition is a matter of convenience in operating the alcohol recovery equipment.

Referring more particularly to the drawing, a hydrocarbon feed stock consisting primarily of hydrocarbons of four carbon atoms and containing about -90% olefins is introduced into agitator i through line 2. Sulfuric acid of about 80-90% strengthis introduced by line 3 into agitator I at a point above the introduction of the olefins. A temperature of -50" C. is maintained in agitator i by means of refrigeration coil 4'. In the agitator the acid and the olefins are thoroughly contacted by means of agitator blade 5, whereupon the olefins are absorbed in the sulfuric acid, forming an acid extract which is removed from the bottom of agitator l1 through line 6. The acid extract removed from the bottom of absorber l by line 6 is introduced into settler i from which unabsorbed oleflns are removed through line B. The extract free of unabsorbed hydrocarbons is removed from settler "i through line 0 and diluted with water introduced through line it to an acid strength of 75%, on a hydrocarbon-free basis. The ex-v tract and water are then passed through mixer ii to hydrolyzer it at a temperature of 50-80 C. Dilutedacid extract containing mono-alkyl sulfates and alcohol is then passed from the bottom of the hydrolyzer through line it and additional water is introduced through line i l to reduce the acid concentration to about 45%, on a hydro- The dilute extract is then passed by line if) and introduced into the top of strippingtower l6 where butyl alcohol is. stripped from the extract by the countercurrent action of steam introduced through line H. By virtue of the dilution with water-introduced through line i l in the usual process of operation and the re- I moval of the alcohols and other volatile oils by steam distillation any polymers, tars, resins or carbonaceous material present are precipitated and clog up the plates of the column l6 and after 7 covered from the column.

the introduction of the acid extract into the top of the stripping tower. The addition of small amounts of this sulfonated material results in dispersing the tarry, resinous and carbonaceous material so that it does not agglomerate and clog'up the plates of the still.

Alcohol is re-' moved from the top of tower it through line 20' and passed to storage as crudralcohol awaiting subsequent finishing operations. Acid extract from which all alcoholhas been removed and which still contains the added sulfonates is removed from the-stri ping still through line 2L. This spent acid is passed" to settler 22 to remove the layer of sulfonates containing polymer, resins, carbon, etc., which is drawn off .through line 23. Purified acid isthen passed to concentrator 24 through line "where it is reconcentratedto 80-90% concentration, andrecycled to the top of absorber i .throughline 3 as the acid used for the absorption of oleflns. 1

The sulfonated compounds found to be most effective for the dispersion of the tars, resins and carbonaceous materials according to the present invention are the oil-soluble sulfonates obtained in preparing white oil by treating lubricating oil distillates having an average molecular weight of about 300, crude hydroxy octyl sulfonates, such as those recovered from waste acids obtained in the manufacture of various alcohols, the water-soluble sulfonates obtained from sulfuric-acid-oll sludges, and various aromatic and aliphatic sulfonates or sulfonic acids. The sulfonates are preferably added in amounts between 9.5 and '2 vol. percent based on the strong acid extract leaving the agitator.

The present invention may be illustrated by the following examples, which are not to be considered as limiting the invention:

Example 1 An acid extract prepared from 88% H2804 and n-butenes by the commercial scaleplant was diluted to 45% H2804 (hydrocarbon-free basis) with water. This extract was fed to a head as previously described. After 10,230 cc. of dilute extract had been stripped the feed rate of extract had not decreased from the initial rate of 1,200 cc./hr.-

Example 3 The above was repeated using a water-soluble sulfonate sludge recovered from the fuming H2804 treatment of a lubricating oil distillate. The same eilect on cleanliness 'of the still was noted. The concentration required was 1-2 vol.

percent'of the stro'n'g acid extract. Example 4 The above was repeated using the oil-soluble sulfonate recovered as a by-product soap from white oil manufacture. The oil-soluble sulfonate "in 1-2 vol. percent concentration of the strong acid extract was effective for dispersion of the tar as shown above.

Although this invention has been described in connection with the preparation of butyl alcohols,

' i'tlis understood that the present disclosure has been made by way'of exam'ple'only and that numerous changes 'in the details may iberesorted to without departing from the spirit "and scope of the invention as hereinafter claimed. For example the invention maybe appliedto the manufacture of ethyl alcohol, isopropyl alcohol, amyl alcohol or other higher'alco hols.

The nature and oblects'of the present invention having thus been set forth and the specific examples of the same given, what is claimed as new anduseful and desired to be secured by Letters Patent is:

1. In a process for recovering alcohol from a acid by distillation to remove alcohol from the hydrolyzed mixture, the improvement which compacked glass column of 1" diameter by 48" length,

stream. When 6000 cc. of the strong acid extract or 10,230 cc. of the diluted extract had been steam stripped the stripping column became plugged so that no more could be fed. The acid was recovered with no tar separating, indicating its deposition in the column. It was later re- Emmple 2 prises carrying out such distillation in the presence of a small amount of an oil soluble sulfonate recovered as a by-product fromwhite oil manufacture. r

, 2. A process according to claim 1 in which the sulfonate 'is present in the amount of between 0.5 and 2 percent by volume of the mixture of alkyl sulfates and sulfuric acid prior to hydrolysis.

3. In a processfor recovering alcohol from a hydrolyzed mixture of alkyl sulfates and sulfuric acid by distillation to remove alcohol from the hydrolyzed mixture. the improvement which comprises carrying out such distillation in the" presence of a small amount of sulfonate recovered as a lay-product in the sulfuric acid treatment of lubricating oils in white oil manufacture.

. HENRY O. MOTIERN,

. FRANCIS M. ARCHIBALD.

- aar'saancas orran UNITED sums PATENTS Roelfsema May 11, 1937 

